Fig. 3

Illustrations of the correlation between sizes (here DBH) of two neighbouring trees distant by r. In the case of two-sided scramble competition (a), the inter-tree competition is equal and the two neighbouring tree sizes are reduced, there is mutual inhibition. In the case of one-sided contest competition (b), one of the two trees is dominant and the other is suppressed due to asymmetric competitive abilities. In the absence of negative association, the neighbouring trees benefit from being close to each other and exercise facilitation (c) promoting mutual stimulation of their growth